New acrylic copolymers and methods for producing same



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Unite l 2 3 {V8 965 acrylate and butyl acrylate. The resins produced byB the addition polymerization method described in said NEW ACRYLICCGPQLYMERS AND NTETEODS p FOR PRODUCING SAME patent do not display thethermoplastic propert1es of the resins of this invention. Instead, theyare thermosetting Norman Gaylord Westbury assign): to Inter- 5 and setto yield a hard baked coating upon curing. Withchernical Corporation,New York, N.Y., a corporation of O i out any commitment on the theoryinvolved, I believe No Drawing. Filed Apr. 20, 1959, Ser. No. 807,289that this difierence is due to a significant difference in 6 Claims.(Cl. 260-895) structure between the theromplastic resins of thisinvention and the thermosetting res-ins described in the patent. Thisinvention relates t0 novel 17013 1116110 materials and 10 i I believethat the ester interchange reaction of this to coating compositioncontaining these new polymeric invention may be shown by the followingstructural materials. More particularly, it relates to permanentlyequation; thermoplastic resinous copolymers produced by the ester Hinterchange reaction of 2,5-endomethylene-A3-tetrahydro- 1 CHTCH 0benzyl alcohol also commonly referred to as Z-hydroxy- A} C :0 =0 2atalyst methyl-S-norbornene with a homopolymer or copolymer I l H OH;containing acrylic ester or methacrylic ester monomers. 0 0 HO CEPCHTOHI These new thermoplastic resins are compatible with n many conventionalthermosetting resins and function as excellent plasticizers whencombined with such thermol H GH H- settmg resins. In add1t1on, solutionsof our novel ther- O GHPO moplastic resins in volatile organic solventsprovide excellent lacquer coatings. Z-hydroXymethyl-S-norbornene 0 0which has the following structure L n 6 EOE oHiiJH fi/ H\ HCCHi-OH Ho(i7HCH -OH 0:0 \C/ H H H Where R has the meaning given above and n is aposiis readily prepared by condensing allyl alcohol with cyclo- 'FInteger lndlcatmg the number of repeatlflg 1111115- pentadiene (US.Patents Nos. 2,596,279 and 2,353,606). 15 to be noted that Wherever thel-hydroxymethyl-i-nor- The homopolymer or ccpolymer reacted with thebornene is incorporated into the copolymer by estermterhydroxymethyl-S-norbornene may be represented as conchange a r q PFnucleus 'f i T1118. 15 mining the f ll i structural unit; not the casewith the add1t1on copolymenzation reaction described in U. S. Patent No.2,838,479. In the reaction of this patent, while most of the reactedacrylic ester of "CH2O-' 2-hydroxymethyl-5-norbornene does polymerizevia the acrylate double bond, thereby resulting in pendant nor- =0 40bornene nuclear similar to those of the resin of this invention, aconsiderable portion of the acrylic ester polymerizes by means of thenorbornene nucleus double bond. where R is a member of the groupconsisting of methyl The latter results in pendant acrylate groups.Accordgroups and hydrogen and R is an alkyl group contain ingly theaddition copolymer of said patent has the following 1 to 8 carbon atoms.ing structural formula:

H H H H H H H H H H ar "'t"%"7"" 0=i7 o=i l OH-0H2 -'0H 0:? OH-CH,--OH(i) O CH-C 2 O Oil-G a 43H; 6H2 {3H2 47H: +152 HGT-5H /(BHOH2 o H-CH:CHGHi-CH CH CHWCH =0 o-oH -on o=0 H H CH=CH 0H=0H =0 oH=o I =0 H H H Theratios of the reactants is not particularly critical. These pendantacrylate groups are substantially re- In fact, the ester interchangereactions have been consponsible for the thermosettmg properties of theresins ducted with ratios of Z-hydroxymethyl-S-norbornene to covered bysaid patent. The setting of said resins upon acrylic ester typecopolymer between 1 to 10 nd 7 to baking is attributable tocross-hnk-ing by means of homo- 10 by weight. The ester interchangereaction is norp lym riz ion of t e pendant acrylate groups or comallycatalyzed by an alkoxide of polyvalent metal pref. polymerization of thependant acry late groups with the erably tetrabutyl titanate or aluminumisopropoxide. P ndant n rbornene groups.

By means of its unique ester interchange reaction, this On the otherhand, as described above, the novel therinvention provides a newpermanently thermoplastic resin moplastic resins of this inventionproduced by an ester which incorporates an acrylic ester type polymerand interchange reaction have no pendant acrylate groups.Z-hydroxymethyl-S-norbornene. They accordingly do not undergo anyappreciable cross- The existing art does not disclose such a novelperlinking upon heating and remain permanently thermomanentlythermoplastic resin. US. Patent No. 2,838,479 plastic. disclosesthermosetting resins produced by the addition The following exampleswill serve to illustrate the prepolymerization of2,5-endomethylene-A3-tetrahydrobenzyl ferred practice of this invention.

3 Example 1 To produce an acrylic ester copolymer, a solution of 645 g.(6.45 moles) of methyl methacrylate, 105 g. (.82 moles) of butylacrylate and 7.5 g. of azobisisobutyronitrile in 875 g. of xylene isadded dropwise over a period of 2 hours to 875 g. of xylene at atemperature of 80 C. The mixture is maintained at 80 C. for anadditional 8 hours. A solids determination indicates a solid content of29.2% by weight which represents 97.4% conversion of monomers tocopolymer.

237 g. (1.9 moles) of 2-hydroxymethyl-5-norbornene are then added to2250 g. of the acrylic ester copolymer solution produced. Since thissolution has a solids content of 29.2%, it is calculated to contain 675g. of copolymer. The mixture is heated to 140 C. to remove any waterwhich may be present.

The mixture is then cooled to 60 C. and 13.1 g. of tetrabutyl titanateare added. The mixture is heated to reflux and a distillate comprising asolution of xylene and the methanol produced by the ester interchangereaction is collected by azeotropic distillation. The distillation iscarried out at vapor temperatures of 120-427 C. and pot temperatures of140l45 C. After 90 ml. of distillate are collected, another 13.1 g. oftetrabutyl titanate are added and the remainder of the distillate iscollected, making a total of 885 g. of distillate collected. Thedistill-ate has a composite refractive index n at 30 C. of 1.4840 whichindicates that the distillate comprises 93% xylene and 7% methanol.Based upon the distillate weight, a total of 61.9 g. of methanol iscalculated to have been collected. This indicates that substantially 1.9moles of methanol was produced by the ester interchange reaction of 1.9moles of 2-hydroxymethyl-5-norbornene with the methacrylic copolymer,thereby resulting in the 100% incorporation of the reacted2-hydroxymethyl-5- norbornene in the copolymer. The resultantthermoplastic resinous copolymer is calculated to have a 3.77:1.9:0.72molar ratio of methylmethacrylatezZ-hyd-roxymethyl-S-norbornene:rnethacrylate butyl acrylate.The final copolymer solution has a 46.3% solids content by weight.

The resinous copolymer is found to be permanently thermoplastic. It doesnot set upon the application of heat.

Example 2 428 g. of Z-hydroxymethyl-S-norbornene are added to 1500 g. ofthe acrylic ester copolymer solution produced in Example 1. Since thissolution has a solids content of 29.2%, it is calculated to contain 450g. of copolymer. The mixture is then heated to 140 C. to remove waterwhich may be present after which it is cooled to 60 C. 11.8 g. oftetrabutyl titanate are added and the mixture is heated to reflux. Asolution of xylene and the methanol produced by the ester interchangereaction is collected by azeotropic distillation. After about 60 ml. ofdistillate have been collected, the refluxing mixture is cooled to 60 C.and another 11.8 g. of tetrabutyl titanate are added. The mixture isagain heated to reflux and another 175 g. of distillate are collected.During this azeotropic distillation, the temperature of the mixturevaried between 130 to 140 C. The product has a solids content of 42% byweight. The viscosity is 148+ poises.

The resinous copolymer produced is found to be permanentlythermoplastic. It does not set upon the application of heat.

Example 3 100 g. of methyl acrylate and 1 g. of azobisisobutyronitrileare added dropwise over a period of 1% hours to 400 g. of xylene at atemperature of 80 C. The mixture is maintained at 80 C. for anadditional 19 hours. To 214 g. of the copolymer solution produced, areadded 21 g. of 2-hydroxymethyl-5-norbornene. The mixture is then heatedto boil ofi any water which may be present.

3 The mixture is cooled to 60 C. and 1.3 grams of tetrabutyl titanateare added. The mixture is heated to reflux and a distillate comprising asolution of xylene and the methanol produced by the ester interchangereaction is distilled oil by azeotropic distillation. After refluxingfor 3 hours another 1.3 grams of tetrabutyl titanate are added.Refluxing is continued for an additional 3 hours until no furtherdistillate comes over. The distillation is conducted at temperaturesbetween 124 and 137 C. The remaining polymer solution has a solidscontent of 23.7% by weight. The reaction product does not set afterheating at 177 C. for /2 hour. It is thermoplastic.

While for the purposes of describing the present invention, I havereferred to copolymers of '2-hydroxymethyl-S-norbornene, it will beunderstood that related homologs can be readily used. Homologs andderivatives may be readily prepared by condensing allyl alcohol withalkyl substituted cyclopentadienes (U.S. Patents No. 2,596,279 and No.2,353,606) and compounds containing two alcoholic hydroxyl groups can beprepared by condensing an unsaturated diol, such as butenediol withcyclopentadiene.

While there have been described what are considered to be the preferredembodiments of this invention, it will be understood that the practiceof this invention is not limited to the resins described in the specificexamples but that various modifications may be made therein withoutdeparting from the scope of the invention as it is defined in theappended claims.

I claim: a I

1. New thermoplastic resins comprising the ester interchange reactionproducts of Z-hydroxymethyl-S-norbornene and a polyacrylate containing arepeating unit having the following structural formula:

IE! where R is a member of the group consisting of a methyl group andhydrogen, and R' is an alkyl group containing from 1 to 8 carbon atomsin the presence of an alkoxide of a polyvalent metal wherein the metalhas a valence of at least 3.

2. The new thermoplastic resin claimed in claim 1 wherein said alkoxideof a polyvalent metal is tetrabutyl titanate.

3. The new thermoplastic resin claimed in claim 1 wherein said repeatingunit is the methyl methacrylate monomer.

4. The new thermoplastic resin claimed in claim 1 wherein said repeatingunit is the methyl acrylate monomer.

5. A method of preparing thermoplastic resins which comprises heatingZ-hydroxymethyl-5-norbornene and a polyacrylate containing a repeatingunit having the following structure:

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS Barrett Mar. 1, 1938 Mus'kat May 11, 1943 6Alder et a1. July 4, 1944 Clifford Nov. 21, 1944 Thomas Feb. 11, 1947 6Nichols June 19, 1951 Tawney Dec. 18, 1957 Haslam et a1. Feb. 4, 1958Biletch June 10, 1958 FOREIGN PATENTS Great Britain June 22, 1938

1. NEW THERMOPLASTIC RESINS COMPRISING THE ESTER INTERCHANGE REACTIONPRODUCTS OF 2-HYDROXYMETHYL-5-NORBORNENE AND A POLACRYLATE CONTAINING AREPEATING UNIT HAVING THE FOLLOWING STRUCTURAL FORMULA: